Resistor structure



Nov. 27, 1956 R. E. DU Bols RES ISTOR STRUCTURE Filed Nov. 12'; 195s 4 Sheets-Sheet, l

' ATTORNEY Nov. 27, 1956 R. E, DU Bols 2,772,337

RESISTOR STRUCTURE Filed Nov. 12, 1953 l 4 sheets-sneer 2 /Om @v50/5,

ATTORNEY INVENTOR rfNov. 27, 1956 R. E. Du BOIS REsIsToR STRUCTURE 4 Sheets-Shea?l 3 Filed Nov. l2, 1953 INVENTOR ,PpmuBO/,

ATTORNEY N0V 27 1956 R. E. DU Bols RESISTOR STRUCTURE 4 Sheets-Sheet 4 Filed Nov. l2, 1953 NWI QN NNM! INVENT OR /Poz-W i 0050/6,

ATTORNEY United States Patent() RESISTOR' STRUCTURE Rober: E. nu manmmna, Imi..

Application November- 12, 1953,'Seral No. 3913566 12.C,laims. (Cl. 201-69): ,Y

This invention relatesgenerally'to resistorl structures and Vmore particularly to improvements ifn mounting structures for relatively heavy duty 4resistor grids'.

The primary object `of this invention, therefore, is to providean improved mounting frame forwresistor grids'.

A more specic object of thisinventionvi's to provide an improved mounting frame forfa` plurality of resistorY grids connected' together in a continuous `resistor incorporating therein structure to permitexpansion and contraction of the resistor over its length under varying temperature conditions-of the resistor.

Another object `of this invention is to provide novel insulator structure in a resistor framenfor supporting a plurality of resistor grids in the frame.

A further object of thisinvention is` to provide novel mounting elements 4forthe. insulators carrying the; resistor grids of the improved, resistorv frame,v

A general object of this'invention4 is, to provide a resistor structure and a mounting frame therefor-whichlend themselves to ready and economical manufacture.

With the foregoingand other objects in View; the invention resides in the following-specilication rand. appended claims, certainembodiments and ,details of construction thereof being illustrated in the accompanying. .drawings in which:

Figure 1 is a broken viewA in side elevation :of the resistor structure of the invention; V

Figure 2 is a partially cutaway planview of Figure il;

Figure 3 is a view taken -along the. lines-3 3 of Figure 2;

Figure 4 is a view in perspective. of the mounting element for securing the resistor elements4 to the mounting frame;

Figure5 isa view takenalong the line 5-5 of Figure24;

Figure 6 is ar view in perspectivetof an insulator `for carrying theA grids, of the `resistor?,structure on the mounting frame;`

Figure 7 is a view .takcn along the '.lines:. 71-'7` of Figure 6;

Figure 8 is an enlarged broken view of a portion of the resistor and frame illustratedein Figure l;

Figure: 9- is an enlarged broken; endxyiew of one. of the resistor grids and the insulators carrying the grid;

Figure l0 is a partial view in side elevation of a modified form of the invention;

Figure ll is partially sectioned end view of another modified form of the invention; and

Figure l2 is sectioned view of the grids taken along the lines 12-12 of Figure 1l.

Referring more particularly to the drawings, a resistor mounting frame 1 is illustrated including end members 2 and 3 and top and bottom members 4 and 5, respectively. The members 4 and 5 are provided with integral mounting flanges 6 and 7 respectively. Mounted within the frame elements, by means to be described, are a plurality of resistor grids 8 connected to each other to form a continuous resistor.

Referring now to Figures 3, 8 and 9 particularly, it

Patented Nov. 27, 1956 ICC will be seen that each grid 7 is welded at its extremity to a mounting pin 9. The mounting pins 9 are U-shaped in structure with the base portions thereof acting as electrical bridging connectors between adjacent grids 8. The ends 10 of pins 9 extend upwardly from the grids 8 and arereceived in guide holes 11 of mounting insulators 12. The holes 11 are of slightly greater diameter than the diameter of the pin ends 10 and are of such a depth as to provide for free sliding movement of the said pin endstherein, as the grids 8 expand and contract under varying temperature conditionsV of the said grids.

The insulators 12 extend over substantially the length of the top and bottom members 4 and 5, and the holes 11 therein are normally spaced to provide for even pluralv grid mounting. As best seen in Figures 3, 4 and 5, channel-shaped mounting clips 13, havingoutwardly iiared ilanges-14 and 15 are utilized to attach the insulator strips 12 to the top and bottom frame members 4 and 5. These ilared or tapered flanges 14 and 15 cooperate with the tapered sides 16 of the insulator 12 to hold the'insulators tightly against the frame members. Bolts 17 extend through frame members 4 and S and the clips- 1-3, and nuts-18 threaded thereon hold the clips 13 firmly in position against the insulator strips.

It will be more apparent from Figures 2 and 3 that the present invention contemplates more than one row of grids 8'. However, it is obvious that terminals and jumpers may be positioned at any desirable points over the length of the resistor structure so that the number of rows or length .of the unit is not critical to this invention.

In the presently illustrated structure of the invention it will further be apparent that the resistor is provided with.twoterminals 19 and 20. Terminal 19 is suitably secured to a mountingfblock 22 secured to the inner wall of end frame member 2. Terminal 20 is likewise secured to a block 21. As shown in Figure l the last grid pin 23 is adjacent to the inner end of terminal 20 and a jumper 24 is provided therebetween. The upper end of the last grid in the other row is welded directly to terminalf 19. This is not illustrated in Figure l in order to avoid confusing the drawing. Suitable jumpers (not shown) may be providedon end member 3 to complete a circuit through` the grids 8 from terminal 19 to terminal 20.

f ln the enlarged detail views, Figures 8 and 9, the grids 8 are illustrated as being provided with stilening dimples 25 for strengthening purposes. The dimpling assists in preventing. sagging or warping of the grids with the possibleshorting-out of resistance material.

' In Figure l0 the grids 8 are shown increasing in concentration toward thecenter of the structure, the mountingholes 26 therefor being more closely spaced in the insulators 12 toward thev center. The purpose of the unequal spacing and concentration of resistance material is-to provide for a more even dissipation of heat from theresistorunder forced draft cooling conditions.

The modified form of the invention illustrated by Figures ll and l2 represents the manner by which even heat dissipation may be obtained in a resistor unit having a plurality of rows of series or parallel connected resistor grids.

As will be obvious from Figure ll, the grids 8 of adjacent rows are of decreasing Width from left to right with the blast cooling coming from the left. Whether the cooling air is directed over the grids from one side or the other depends on whether they are connected in parallel or series, as indicated.

Figure l2 represents the grids 8 as being of varied thickness as well as widths. This is a matter of design choice and the grid rows may not be of varied thickness. By correct designing, however, in such multiple row resistors, the avoidance of hot spots is attained by utilizing grids of varying widths and, or thicknesses.

It will now be obvious that as the resistor heats up when in use, the individual grids acting in adjacent pairs will expand longitudinally, forcing the bridging pins further into the holes 11 of the insulators 12. Thus a complete means for temperature compensation is provided over the entire length of the structure. The provision of the dimple 25 acts to assist in creating turbulence in air passing over the grids to obtain increased dissipation of heat to the air.

Thus it will be seen that this invention provides a compact, economical self-temperature compensating resistor structure which will lend itself to many varied forms depending on a particular commercial application,

I claim:

1. A resistor structure comprising a mounting frame including top and bottom frame members, a plurality of insulator strips, said strips being provided with a plurality of spaced holes, clip means cooperating with said strips to secure the strips to the top and bottom frame members, and resistor means with a plurality of grid elements carried by said insulator strips, the said resistor means cooperating with the spaced holes along said insulators to permit longitudinal expansion and contraction of the grid elements under varying grid temperature conditions.

2. A resistor structure comprising a mounting frame; insulators carried by the frame, said insulators being provided with holes, a plurality of resistor grids arranged side by side Within said frame, U-shaped pins connecting alternate ends of adjacent grids together, said pins cooperating with the holes in the insulators to carry the grids for free relative movement to the frame.

3. A resistor structure comprising a mounting frame, insulator strips carried by the frame, said strips being provided with a plurality of spaced holes, a plurality of resistor grids arranged side by side within said frame, U-shaped pins connecting alternate ends of adjacent grids together, said pins cooperating with the holes in the insulator strips to carry the grids for free relative movement to the frame.

4. A resistor structure comprising a mounting frame, a plurality of insulators, said insulators being provided with holes, clips means cooperating with said insulators to secure the insulators to the frame, a plurality of resistor grids arranged side by side within said frame, U-shaped pins connecting alternate ends of adjacent grids together, said pins also cooperating with the holes in the insulators to carry the grids for free relative movement to the frame.

5. A resistor structure comprising a mounting frame, a plurality of insulators, said insulators being provided with holes, clips means cooperating with said insulators to secure the insulators to the frame, a plurality of resistor grids arranged side by side within said frame, pins connecting alternate ends of adjacent grids together, said pins also cooperating with the holes in the insulators to carry the grids for free relative movement to the frame.

6. A resistor structure, comprising a mounting frame,

a plurality of insulator strips, said strips having tapered side walls and being provided with a plurality of spaced holes, clip means having flared side ilanges cooperating with the tapered walls of the insulators to secure said insulators to the frame, a plurality of resistor grids arranged side by side within said frame, and means connecting alternate ends of adjacent grids together, said connecting means cooperating with the holes in the insulator strips to carry the grids for free relative movement within the frame.

7. A resistor structure comprising a mounting frame, insulators carried by the frame, a plurality of rows of continuous resistors carried by said insulators for free movement relative to the frame under varying grid ternperature conditions, said continuous resistors being of decreasing thickness and width in adjacent rows from one side of the structure to the other.

8. A resistor structure comprising a mounting frame, insulators carried by the frame, a plurality of rows of continuous resistors carried by said insulators for free movement relative to the frame under varying grid temperature conditions, said continuous resistors being of decreasing thickness in adjacent rows from one side of the structure to the other.

9. A resistor structure comprising a mounting frame, insulators carried by the frame, a plurality of rows of continuous resistors carried by said insulators for free movement relative to the frame under varying grid ternperature conditions, said continuous resistors being of decreasing width in adjacent rows from one side of the structure to the other. v

10. A resistor structure comprising a mounting frame and a plurality of rows of continuous resistors carried by the frame, said continuous resistors being of decreasing width in adjacent rows from one side of the structure to the other.

11. A resistor structure comprising a mounting frame and a plurality of rows of continuous resistors carried by the frame, said continuous resistors being of decreasing thickness in adjacent rows from one side of the structure to the other.

12. A resistor structure comprising a mounting frame and a plurality of rows of continuous resistors carried by the frame, said continuous resistors being of decreas ing thickness and width in adjacent rows from one side of the structure to the other.

References Cited in the file of this patent UNITED STATES PATENTS Tas-iff 

